Fluid compressor



C. W. METZGAR.

FLUID COMPRESSOR.

APPLICATION FI1.ED AUG 4. 1921.

1,427,835, PatentedSept. 5, 1922.

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INVENTOR HIS ATTOR Y C. W. METZGAR.

FLUID COMPRESSOR.

APPLICATION FILED Aue 4. I921.

Patent ed Sept. 5, 1922.

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' INVE.NTOR CZeslTerW/Hf C. W. METZGAR.

FLUID COMPRESSOR. APPLICATION FILED AUG=4,1921.

PatentedSept. 5, 1922,

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T A s FFICE.

CHESTER W. METZGAR, OF EASTON, PENNSYLVANIA, ASSIGNOR TO INGERSOLL- RANDCOMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

FLUID COMPRESSOR.

Application filed August 4, 1921. Serial No. 489,702.

To all whom it may concern:

Be it known that I, CHESTER W. Mn'rz- GAR, a citizen of the UnitedStates, and a resident of Easton, county of Northamptonand State ofPennsylvania, have invented a certain Fluid Compressor, of which thefollowingis a specification, accompanied by drawings.

This mvention relates to compressors, but more particularly to acompressor for compressing gas with varying discharge pressures.

In pumping gas, for instance, from a gas bell operated from any suitablesource, for use at a remote point, as in a city supply, the conditionarises in which the compressor shall continue to operate for a shorttime, without however, pumping gas from the gas bell. Otherwisecontinuous pumping would drain down the gas in the bell to anundesirable point.

A regulator of the type disclosed in my co-pending application, SerialNo. 489,626 filed Aug. 3, 1921, has been selected to illustrate theinvention, which regulator will unload the compremor step by stepaccording to successive changes in the predetermined line pressure, andwill completely unload the compressor at this pressure as usual withthis type of regulator.

The object of the present invention is to enable the compressor to becompletely unloaded with smaller clearance pockets than are requiredwith the ordinary way of unloading. In accordance with this invention, Iprovide operative means for utilizing a portion of the bore of one endof one cylinder as a. clearance space for the other cylinder forunloading the compressor. One end of either cylinder may be utilized asa clearance space for the other cylinder.

The invention is shown in one of its preferred forms in the accompanyingdrawings, in which Figure 1 is a diagrammatic view partly inlongitudinal section of a portion of a compressorembodying theinvention,

Figure 2 is an enlarged detail longitudinal sectional view of one of theclearance valves,

Figure 3 is an end elevation of the compressor, and

Figures 4 to 7 inclusive, are diagrammatic views showing the relativepositions of the pistons in the two cylinders during a completerevolution of the crank shaft.

. Referring to the drawings, the compres- I sor may be of any suitabletype, but I have chosen for illustrative purposes to show a single stageduplex compressor having two low pressure cylinders A and C and twodouble acting pistons B and D. The pistons, having the piston rods E andF may be driven from any suitable source or sources of power (not shown)and the cylinders are provided respectively with clearance pockets G andH, and J and K, communicating with the cylinders and controlled bysuitable clearance valves T contained in the valve casings 1, 2, 3 and4:, mounted on the heads 0 and P of the cylinder A, and similar valves Tin similar valve casings 1, 2, 3, and 4c, mounted on the air heads Q,and R of the cylinder B. The compressor valves S for the cylinder A andthe valves U for the cylinder B, which may be of the plate type, aremounted in the air heads and serve as inlet or discharge valves in theusual manner. The compressor cylinders are assumed to be connected bysuitable piping to each other and to the main receiver V, the piping notbeing shown for the sake of simplicity. The chambers W in the air heads,in which the clearance valves T opgerate, communicate with the variousclearance pockets G, H, J and K in the cylinders A and C, by means ofthe ports X, and the corresponding pockets for opposite ends of thecylinder are in this instance connected by cross connections Y,communicating with the clearance pockets through the portsZ andcontrolled by by-pass valves a operating in the casings 5 and 6.

The clearance valves T are similar to the by-pass valves a, and arepreferably of the construction shown in detail in Figure 2, in which thevalve seat 6 is provided with a guide 0, over which the hollow head (1of a'valve T or a slides, and upon which the valve is guided. A springe, compressed between the guide 0 and the valve head 03, tends to openthe valve when line pressure from the receiver C, which tends to closethe valve, is relieved. A pin 7 passing through a stufling box 9 bearsagainst the valve head I) and against the iston h operating in thepistonchamber eceiver pressure issupplied to the chamber 9' behind thepiston it through a Suitable pipe connection. The by-pass valves a areprovided with manual means for rendering the valve inoperative, byholding them closed and for this purpose the valve casings 5 and 6 areprovided with adjustable set screws k in the casing heads 0. The setscrews may be provide with squared ends p and lock nuts 9 and when a setscrew is screwed in a sufficient distance, the piston b will be forcedinwardly and the by-pass valve will be maintained closed. I

The clearance valves T and the bypass valves a. are all adapted to bemaintained in closed position by receiver pressure from the receiver V,and the valve casings are all connected by suitable pipe connections tothe valve chest 'I' of a regulator s, of the type described in mycopending application, Serial No. 489,626 filed August] 3, 1921. Thisregulator operates in substantially the same manner as the regulatordisclosed in United States Patents No. 1,027,757;

1,027,758; and 1,027,760, granted May 26, 1912, to William Prellwitz,assignor to Ingersoll-Rand Company. In such 'a regulator the movementsof a plurality of main regulating valves within the valve chest 7' forcontrolling the loading and unloading of the compressor, are in turncontrolled by an auxiliary regulator valve within the valve chest 1'.With such a regulator, clearance pockets of the compressor are broughtinto and out of communication with the interior of the compressorcylinders, for securing a step by step unloading or loading of thecompressor as the .fluid in the main receiver tank' V reachessuccessively attained pressures.

Without describing the internal construction of the regulator s it issuflicient for the purposes of this invention to describe the mode ofoperation. The valve casings 1, 2, 3 and 4 of the cylinder A areconnected to the similarly numbered valve casings 1,2,- 3 and 4 of thecylinder B by means of the pipes 1*, 2 3? and 4 which are in turnconnected by. branch pipes 1", 2", 3 and 4 to the valve chest 1* of theregulator s, so

that the clearance valves T are operated in pairs. The valve casings 5and 6 of the by-pass valves a are connected by branch pipes 5 and 6direct to the valve chest r of the regulator s, and the construction issuch that when the last pair of clearance valves T in the valve casings"4 is opened, in the successive step b step operation of the unloading,by relieving thepressure behind the heads of said clearance valves T,the by-pass valves a operating in the casings 5 and 6 are opened oneafter the other in order to open communication between the oppositeclearance pockets G and J, and H and. K. The last step of unloading iseffected by the opening of the bypass valve a operating in the valvecasing 6.

Before describing the manner in which one end of one cylinder isutilized as a clearance space for the other cylinder, in accordance withthe diagrams of Figures 4 to 7 inclusive, the remainder of theregulating apparatus will be described. I The valve chest '1" of theregulator s is connected by a pipe t to the pipe u, which connects thereceiver tank V to casing 'v of a fluid actuated device, having a leverarm w adapted to be connected by means of a rod w to the auxiliarycontrolling valve of the regulator s. The lever '10 is pivoted at y onthe frame v and the weight of the lever is carried on a pin 2,'movablein any suitable manner in accordance with successively attained re-'ceiver pressures. The end of the lever w may be weighted by the weights2 and a rod 3 pivoted at 4 to the lever to extends through the frame ofthe device and is provided with a cap 5 between which and the frame, thespring 6 is compressed for resisting upward movement of the lever. Fluidpressure is exhausted fromthe valve chest 1 through the exhaust pipe 8communicating with the bottom of the valve chest, and exhaust pipe 9communicating with the top of the valve chest through the frame a of thecontrolling device. In the position of the parts indicated in Figure 1,the controlling lever "L0 has been raised by fluid pressure in thereceiver tank V to its uppe'rmost position in which case, pressure hasbeen relieved from behind the heads or pistons h of all the clearancevalves T and the two by-pass valves (1, so that all of said valves havebeen successively automatically opened, and the compressor is completelyunloaded.

Referring more particularly to Figures 4, 5, 6 and 7, obviously, ifdesired, the by pass valves a may be hand operated valves having thehandles 10 and 11 for manual operation, instead of automatic operation.as shown in, Figure 1. In the operation of the apparatus, let it beassumed that all the clearance valves T and the. two by-pass valves aare open. In Figure 4 the pistons B and D are moving in the samedirection as indicated by the arrows and compressing from intakepressure to discharge pressure for only one half of a stroke.

In Figure 5 the pistons B and D are through with compression, with thegas in the clearance spaces at discharge pressure. The clearance spacesconsist of substantially one half of the compression space of one end 12of the cylinder A, and the clearance pockets H and K in both cylinders.because the space 12 of the-cylinder A is in communication with thepockets K of the cylinder C through the cross connection Y.

The pistons B and D then move in oppo-.

site directions for one half of a stroke, displacing the gas in thespace 12 of the cylinder A until the position of Figure ,6 is reached,the pressure remaining constant. The gas from the space 12 of thecylinder A has been displaced to the 'space 13 of the cylinder C.

In Figure 6 the pistonsv B and D are through with displacement and areabout to move in the same direction, for one half of a stroke, butopposite to the direction indicated in Figure 4. The gas in theclearance pockets H and K of both cylinders and in the space 13 of thecylinder C, is expanded from discharge pressure to intake pressure.

In the position of the pistons B and D in Figure 7, the gas is throughwith ex ansions, andthe travel of the piston D is a out to reverse sothat the pistons will be moving in'opposite directions for one half of astroke, displacing the gas at intake pressure from the cylinder C to thecylinder. A.

The displacement of gas-from one-cylinder to another described inconnection with the spaces 12 and 13 atone end of the cylinders takesplace in a similar manner for,

the spaces 14: and 15 at the opposite ends of the cylinders.Displacement of gas takes place twice in each cylinder and ,for eachrevolution of the' compressor.

I claim:

1. In a fluid compressor, the combination of two cylinders and pistonsreciprocating therein, and means operable for utilizing a portion of thebore at one end of one cylinder as a clearance space for the othercylinder for unloading the compressor.

2. In a fluid compressor, -thecombination of two cylinders and pistonsreciprocating therein, and cans operable for utilizinga portion of thebore at one end of either cylinder as a clearance space for the othercylinder for unloading the compressor.

3. In a fluid compressor, the combination of two cylinders and doubleacting pistons reciprocating therein, and means operable for utilizingportions of the cylinder bores at both ends of either cylinder asclearance spaces for the other cylinder for unloading the compressor.

4. In a fluid compressor, the combination of two cylinders havingclearance pockets adapted to be placed in communication with thecylinders respectively, pistons reciprocating in the cylinder bores, andmeans operable 'for utilizing a portion of the bore at one end of onecylinder as an additionalclearance space for the other cylinder forunloading the compressor.

5. In a fluid compressor, the combination of two cylinders havingclearancepockets adapted to be placed in communication with thecylinders respectively, pistons reciprocating in the cylinder bores, andmeans operable for utilizing a portion of the bore at one end of eithercylinder as an additional clearance space for the other cylinder.

6. In a fluid compressor, the combination of two cylinders havingclearance pockets adapted to be placed in communication with thecylinders respectively, double acting pistons reciprocating in thecylinder bores, and means operable for utilizing portions of thecylinders bores at both ends of either cylinder as additional clearancespaces for the other cylinder for unloading the compressor.

7. In a fluid compressor, the combination of two cylinders and doubleacting pistons reciprocating therein and means operable for utilizingportions of the cylinder bores at opposite ends of either cylinder asclearance spaces for corresponding ends of the other cylinder forunloading the compressor.

8. In a fluid compressor, the combination of two cylinders havingclearance pockets adapted to be placed in communication with thecylinders respectively, double acting pistons reciprocating in thecylinder bores, and means operable for utilizing portions of thecylinder bores, at opposite ends of either cylinder as additionalclearance spaces for corresponding ends of the other cylinder forunloading the compressor.

9. In a fluid compressor the combination of two cylinders and pistonsreciprocating therein, a'connection independent of the discharge lineafl'ording communication between the compression spaces of the cylinderbores and means for controlling said connection, whereby a portion ofthe compression space of one cylinder may be utilized as the clearancespace for the other cylinder for unloading the compressor.

10. In a fluidcompressor, the combination of two cylinders and pistonsreciprocating therein, cross connections independent of the dischargelmeafi'ording communication be- .at corresponding ends of the cylinderbores,

and means for controlling said connections, whereby the compressionspaces of either cylinder bore may be utilized as clearance spaces foreither end of the other cylinder for unloading the compressor.

In testimony whereof Ihave signed this specification.

CHESTER W. METZGAR.

